1. Field of the Invention
The invention relates to a safety ski binding incorporating a toe and a heel binding and an electronic circuit, with an electronic display device and a sensor system for detecting at least one set safety release value for the safety binding.
2. The Prior Art
Patent specification EP 0 469 453 A1 discloses a safety ski binding with an electronic device for displaying the set safety release force. A display is provided, which displays the values of settings detected and determined by a sensor and an electronic evaluation device. A power supply in the form of a battery is also provided, so that the electrical components can be supplied with power when a switch is activated and deactivated. The sensor, by means of which the set safety release value is detected, is provided in the form of a position sensor, which delivers a characteristic electric sensor signal depending on the position of an adjusting screw used to set the safety release value. It is proposed that a capacitive sensor, an inductive sensor or a plurality of micro-switches should be used for the sensor. Another suggestion is that a potentiometer and an adjustable resistor be used as a means of electronically detecting the respective position of the adjusting screw. The disadvantage of this system is that an analogue signal evaluation of the virtually static or absolute position sensors is necessary, which means that the electronic components have a high sensitivity to interference and a low output range. Although this system enables the safety release value set at any one time to be electronically detected and presented on a display, it is not possible to detect changes in the safety release value.
An electronic display device for indicating the release force set on a safety ski binding is known from patent specification DE 33 43 047 A1. In this case, the spring-biassing action of the releasing mechanism is detected by an electromechanical transformer, which converts the prevailing spring biassing force into electrical information. An electronic circuit converts this information to a digital format so that it can be presented on a digital display system. A potentiometer is also proposed, which measures any variation of the adjusting screw relative to the binding housing. Here again, problems can arise in respect of processing the signal as well as the resistance of the electronic system to interference due to the analogue signal evaluation of the sensor measuring absolute force or pressure and the proposed ohmic potentiometer.
Patent specification DE 29 26 385 A1 and patent document U.S. Pat. No. 4,311,321 A belonging to the same patent family disclose a safety ski binding with several electric switching elements for detecting a whole range of operating states of a safety ski binding. In this case, both the toe binding and the heel binding are provided with electrical switch contacts, by means of which various states can be detected, such as, for example any excess accumulation of snow, wear of the soles, incorrect clamping pressures, incorrect height settings of the sole holder and open and closed heel bindings. These single-pole or multi-pole switch contacts, in particular the grouped normally open contacts or switch contacts, are disposed on the toe binding and heel binding and are integrated by means of an electric power supply and a display lamp to form an electric display circuit. If one of the switch contacts is activated due to the occurrence of safety-critical or incorrect states, the display lamp is illuminated or a summer is activated, indicating the fact that the binding has assumed an admissible or safety-critical state. The disadvantage of this system is that when the display lamp is illuminated or flashes, it is not evident what inadmissible operating state has occurred and the user has to make several attempts to find out what the problem is in order to take appropriate measures to return to the correct status. Quite apart from the fact that this display device offers very little in the way of meaningful information, another disadvantage of this system is that the electrical wire connections between the switch elements of the toe binding and the power supply system and display lamp as well as between the switch elements of the heel binding and the power supply system and display lamp restrict the mechanical variability of the ski binding parts and the wire connections must be capable of withstanding high electromechanical demands.
Patent specification DE 32 16 522 A1 discloses a safety ski binding with two bindings and an electrically controlled safety release mechanism which is operated in the event of dangerously high forces. In this case, a sensor is provided in at least one of the bindings, which detects the prevailing forces and stresses and transmits them contactlessly to a signal processing circuit housed in the ski body. In particular, there is no galvanic or electrically conductive connection between the sensor in the binding and the signal processing circuit in the ski body. A transmitter-receiver system is provided for this purpose, in the form of inductively coupled coils or isolated capacitively coupled conductive films or surfaces, for example. Both the sensor signal and also the electrical power needed to operate the sensor and the electromechanical release mechanism in the binding body are transmitted via this transmitter and receiver system. The disadvantage of this system is that high electric outputs are necessary in order to ensure reliable signal and power transmission across a distance of a few centimeters. There is no mention of a system for displaying useful or important states and settings in this earlier known binding.
Patent specification U.S. Pat. No. 4,502,146 A describes a setting means for setting values in a ski binding electronic system without the need for contacts. In this instance, Hall-effect sensors, light-sensitive sensors or piezoelectric devices are used to change values in a system of binding electronics which is inaccessible or encapsulated. This obviates the need for guides and rotary mountings needed for potentiometers or other electromechanical adjusting elements, which often cause problems due to sealing because ingress by moisture poses a risk of short-circuiting or distortion of the actual conditions prevailing at any one time. Although the proposed adjusting means make it possible to set and adapt electronic settings without contact and without any susceptibility to external influences, such as moisture, for example, the proposed design does not allow the safety settings or prevailing states of a safety ski binding to be checked.
Patent specification AT 404 901 B discloses a ski binding with an electronic display device and a sensor system, by means of which the relative position of the ski binding with respect to the ski or the distance between the toe and heel binding can be detected and displayed. Travel or force measurement transmitters are also proposed, by means of which the releasing force set for the ski binding is measured and transmitted via wires to the evaluation device, thereby enabling the position values to be shown in the form of a digital presentation on the display. The disadvantage of this system is that these line connections between the respective measurement transmitters or sensors and the display device make the ski binding more complex and the range of electronic functions of the proposed ski binding is limited due to the degree of complexity involved in achieving a reliable signal or power transmission. In addition, because the range of functions performed by the components is predefined, there is barely any possibility of extending them subsequently. The line connections between the electronic components are also susceptible to breakage when exposed to stress or, alternatively, extensive electromechanical measures have to be taken to compensate for this, increasing complexity still further and incurring a considerable increase in costs.